1. Technical Field
The present invention relates to an ink set, an ink container, a liquid ejecting apparatus, an ink-jet recording process, and a recorded article. More, specifically, the invention relates to an ink set that can form a film having metallic gloss, an ink container containing the ink set, a liquid ejecting apparatus provided with the ink container, an ink-jet recording process using the ink set, and a recorded article recorded by the ink-jet recording process.
2. Related Art
In order to form a film having metallic gloss on a printing material, a gold-colored powder or silver-colored powder that is formed from brass or aluminum fine particles has been used as a pigment of a printing ink, or hot stamping using a metal foil or thermal transfer printing using a metal foil has been employed.
However, since the gold-colored powder or the silver-colored powder used has a large average particle diameter of 10 to 30 μm, the film of a printing ink containing such a metal powder is difficult to have specular gloss though it can have frosted metallic gloss. In the hot stamping or thermal transfer printing that uses a metal foil, an adhesion is applied to a recording medium, and then a smooth metal foil is pressed onto the adhesion. The recording medium and the metal foil being in adhered to each other are heated to be thermally fused. Consequently, though relatively high gloss can be achieved, the number of printing processes is increased. In addition, since a pressure and heat are applied to the recording medium during the printing processes, the recording medium is limited to one having sufficient resistivity to heat and deformation.
Recently, ink jet is frequently applied to printing. One of such applications is metallic printing. For example, JP-A-2002-179960 discloses an ink-jet printing technique using an ink composition containing a pigment prepared by forming a metal coating on the surfaces of spherical plastic particles. However, the particles are required to be deformed into an oblate shape and to have a smooth surface in order to obtain high metallic gloss. Therefore, in this technique, it is required to simultaneously conduct pressing with a roller and heating, and consequently a complicated apparatus and manufacturing process is unavoidable. Furthermore, recording media that can be used are limited.
Furthermore, JP-A-2003-292836 and JP-A-2003-306625 disclose a technique using an ink composition in which a colloid of a noble metal such as gold or silver is dispersed. However, the noble metal colloid develops a color caused by plasmon absorption when the particle diameter is reduced to several to several tens nanometers for providing a priority in the dispersion stability. Consequently, the ink composition cannot achieve metallic gloss. In such a case, in order to obtain high metallic gloss, a film formed by using the ink composition is dried and then heated so that the colloidal particles are fused. However, in these techniques, even if metallic gloss can be obtained, it is difficult to obtain a uniform surface with high metallic specular gloss, such 20-degree, 60-degree, and 85-degree specular glosses exceeding 200, 200, and 100, respectively. Alternatively, in a case that the particle diameter is increased for providing a priority in the metallic gloss, the dispersion stability is decreased to disadvantageously cause aggregation and precipitation. Accordingly, the storage life of the ink composition is significantly decreased. Furthermore, it is obvious that the use of a noble metal material significantly increases the cost of the ink composition, and therefore the ink composition can be used in a high-value-added purpose only and is thus disadvantageous.
Furthermore, there is known a method using a metallic ink composition prepared by mixing a metal pigment and a coloring material as a single ink composition. In this method, there are problems such that the metal pigment and the coloring material are separated during printing and that only the metal pigment is precipitated and aggregated during storage of the ink composition. When this ink composition is used for printing, only the coloring material is absorbed by a recording medium and the metal pigment alone remains at the surface to cause failed printing such as ununiform image formation with decoloration or irregular color.